#include <stdio.h>
int f(int b[ ][4])
{ int i,j,s=0;
for(j=0;j<4;j++)
 { i=j;
 if(i>2) i=3-j;
 s+=b[i][j];
 }
return s;
}
int main( )
{ int a[4][4]={{1,2,3,4},{5,6,7,8},{9,10,11,12},{13,14,15,16}};
printf("%d\n",f(a) );
return 0;
}